#include<bits/stdc++.h>
#define ONLINE_JUDGE
#define ll long long
#define ull unsigned long long
using namespace std;

const int N = 1e6 + 10, INF = 0x3f3f3f3f;

int n;
string s;

int find()
{
    for (int i = 0;i < n - 1;i++)
        if (s[i] > s[i + 1]) return i;
    return -1;
}

void solve()
{
    cin >> n >> s;
    int p = find();
    if (p == -1) { cout << s << '\n'; return; }
    int ch = s[p];
    s.erase(s.begin() + p);
    p++;
    while (p < n - 1 && s[p] <= ch) p++;
    s.insert(s.begin() + p, ch);
    cout << s << '\n';
}

signed main()
{
    // ios::sync_with_stdio(0);
    // cin.tie(0);cout.tie(0);
#ifndef ONLINE_JUDGE
    std::istringstream in(R"()");
    std::cin.rdbuf(in.rdbuf());
#endif
    int T = 1;
    cin >> T;
    for (int i = 1;i <= T;i++) {
        solve();
    }
}